This invention relates to a novel self-closing fire rated floor door. More particularly, this invention pertains to a novel floor door which uses one or more fusible plugs and one or more compressed gas cylinders for automatically closing the floor door when ambient temperature rises above a predetermined temperature, due to a fire.
Building codes and regulations passed by regulatory authorities require that multi-floor buildings, such as hotels, office towers and the like, meet stringent fire ratings. Such codes and regulations require that the multi-floor structures use fire resistant materials such as fire proof panels, and other structural elements so that they stop or inhibit the spread of fire if a fire occurs. Doors, walls, floors, ceilings, and the like, in such buildings must be constructed to pass specific fire ratings, thereby enhancing the overall safety of the multi-story building structures.
In many multi-story buildings, devices described as floor doors are installed on each floor, or on some floors, and are used to enable one or more persons to access crawl spaces or gain access through fire rated floors, or pass equipment from one floor to another. Normally, such floor doors are in a closed position but sometimes they are in an open position. If a fire breaks out, and the floor door is open, it is necessary that the door be closed to prevent the transport of fire and smoke from one floor to another floor. A number of techniques have been developed over the years for causing doors, vents and floor doors to automatically close when fire conditions are encountered.
Two U.S. patents, namely, U.S. Pat. No. 5,565,274, granted Oct. 15, 1996, and U.S. Pat. No. 5,554,433, granted Sep. 10, 1996, Perrone, Jr., et al., disclose horizontally hinged covers for use in ceiling/floors. The covers are said to be highly fire resistant and in the event of fire automatically close. The door as disclosed preferably utilizes a multilayer construction comprising an intumescent lower (inner) layer, an intermediate structural layer and a top (outer) layer of a cementitious material. The horizontally hinged door utilizes an automatic closing system in the event of fire comprising a fusible link which activates a pressurized gas source to close the door. The pressurized gas source is automatically purged when the door is closed to prevent explosion of the pressurized gas source. The fusible link also actuates (opens) a hydraulic valve to allow the flow of hydraulic fluid from a pneumatic/hydraulic housing which is used with a movable rod to open and close the door.
U.S. Pat. No. 3,589,065, granted Jun. 29, 1971, Watson, discloses a fire vent hatch which has a housing with upstanding sidewalls and a cover pivotally secured to one of the sidewalls. A pair of rams are mounted on the housing to raise the cover, the rams being connected to a sealed container containing gas under pressure. The lower end of the rams are each pivotally connected to an arm which in turn is pivotally connected to the housing, the arms swinging downwardly when the rams are actuated. A restrictor is provided to throttle the flow of gas to the cover. A scissor latch is provided for holding the cover in the closed position. Thermally and manually controlled means are provided to release the gas to the rams and to open the latch. Temperature controlled means are provided to control the release of the fluid and the release of a scissor latch. This latter means has a spring which is restrained by the use of a fusible link and release mechanism which can be actuated manually if desired.
U.S. Pat. No. 4,043,128, granted Aug. 23, 1977, Bendler, et al., discloses a door apparatus for fire protection purposes including a compressed-gas cartridge device and a thermally responsive triggering mechanism. The triggering mechanism includes a striker which is forcibly driven toward the compressed-gas cartridge device and a locking device for maintaining the striker at a specified distance from the compressed-gas cartridge device. Another end portion of the locking device is biased against a blocking device with the blocking device being disposed between the other end portion of the locking device and an abutment member. The blocking device is set to respond to temperatures above a predetermined temperature. This enables displacement of the locking device and the striker thereby moves toward the compressed-gas cartridge device, thereby closing the door.
The invention is directed to a self-closing fire rated floor door assembly comprising: (a) a fire rated frame with an opening therethrough; (b) a fire rated door hingedly connected to the frame and cooperating with the opening; (c) a fluid cylinder which is pivotally connected to the frame and the door, the cylinder when pressurized with fluid opening the door relative to the frame, and when depressurized, closing the door relative to the frame; (d) a fusible plug, rated according to a specific temperature, connected in fluid-tight manner with the fluid cylinder.
The assembly can include a pair of cylinders, which can be gas cylinders, the first gas cylinder being located on one side of the frame and the second gas cylinder being located on an opposite side of the frame. The pair of gas cylinders can be connected to the fusible plug by a gas-tight gas line.
The assembly can include a second fusible plug connected to a pair of gas cylinders, the first fusible plug being located at one side of the frame, and the second fusible plug being located at an opposite side of the frame. The pair of fusible plugs can be connected to the pair of gas cylinders by a series of gas-tight tubes, and a gas distribution manifold.
The fusible plug can be constructed of a hollow, elongated tube, with a gas fitting at one end adapted to engage with a gas tube, and a solder plug located in the interior of the tube at the end opposite the gas fitting, the solder being engineered to melt at a specified temperature.
The cylinder at one end can be connected to a cylinder manifold which can be pivotally mounted in a bracket secured to the frame, the cylinder manifold having formed therein a first opening which can receive an aircraft needle valve and a second opening which can receive a bleed connector valve. The cylinder manifold can have an O-ring in the interior thereof, and at one end an extension for receiving a bolt which can connect pivotally to a bracket secured to the frame. In some cases, for large doors, two or more cylinders, and two or more fusible plugs can be used.